Microfluidics deals with the precise control and manipulation of small volumes of fluids that are typically constrained to micrometer-length scale channels and to volumes typically in the sub-milliliter range. Prominent features of microfluidics originate from the peculiar behavior that liquids exhibit at the micrometer length scale. Flow of liquids in microfluidics is typically laminar. Volumes well below one nanoliter can be reached by fabricating structures with lateral dimensions in the micrometer range. Microfluidic devices generally refer to micro-fabricated devices, which are used for pumping, sampling, mixing, analyzing and dosing liquids.
A microfluidic probe is a device for depositing, retrieving, transporting, delivering, and/or removing liquids, in particular liquids containing chemical and/or biochemical substances. For example, microfluidic probes can be used in the fields of diagnostic medicine, pathology, pharmacology and various branches of analytical chemistry. Microfluidic probes can also be used for performing molecular biology procedures for enzymatic analysis, deoxyribonucleic acid (DNA) analysis and proteomics.
Microfluidic probe (MFP) systems often require a complex fluid handling instrumentation, which may notably involve: a spatial positioning system (to control the position of the probe with respect to a surface to be processed), and various pressure sources (to control the flow rate of liquid being dispensed). For example, a quite sophisticated instrumentation is typically needed to localize (bio)chemicals on surfaces, which prevents the use of most microfluidic probe systems outside of specialized laboratories. That is, the localization of chemicals as achieved today by the MFP technology typically requires active fluidic handling (expensive) systems that are intended for use in laboratory settings and require precise positioning systems, as well as complex vacuum systems.